The foodstuffs industry makes available to consumers deep-frozen foodstuffs, more particularly fish, in small portions, for example in the shape of, small rods, trapeziums or similar shapes. To obtain portions of trapezoidal shape, in practice three different possible methods are used:
1. Two rods with complementary cross-sections having the trapezoidal shape of the portions are brought together and the portions are cut therefrom in slices.
2. Parallelipipedic slices twice the size of the required portions are brought together in a stack and parted jointly substantially diagonally.
3. Slabs are divided into slices twice the size of the portions, and then these parallelipipedic slices are punched through substantially diagonally. All these methods are expensive and involve cutting losses.